Method for making and insulating a coil tap

ABSTRACT

A winding about a core forming a transformer coil for use as for a battery charger having a plurality of leads tapped onto various turns thereof wherein tapping a lead onto one of the turns of said winding consists of stripping one end of said lead, securing said stripped end of said lead to a turn of said winding to form a tap, sliding a sleeve of flexible insulating material onto said lead, slitting the end of said sleeve adjacent said tap forming a flap portion, folding said flap portion of said sleeve about said tap and onto the adjacent portion of said sleeve and overlying said flap portion with subsequent turns of said winding of said coil.

United States Patent [191 Smith 5] Dec. 16, 1975 [54] METHOD FOR MAKING AND INSULATING 2,661,446 12/1953 Adcock 29/605 A COIL TAP 3,488,839 1/1970 Proxmire 3,766,506 10/1973 Gaty 336/192 [75] Inventor: Leonard S. Smith, Minneapolis,

Primary Examiner-C. W. Lanham [73] Assignee; Centur Mf C I Assistant Examiner-James R. Duzan Mi li Mi Attorney, Agent, or Firm-Leo Gregory [22] Filed. Jan. 10, 1975 ABSTRACT 1 1 p N05 5409283 A winding about a core forming a transformer coil for use as for a battery charger having a plurality of leads 52 us. Cl. 29/605; 29/628; 336/192; tapped Onto various turns thereof wherein tapping 336/207 lead onto one of the turns of said winding consists of [51] Int. Cl. H01F 7/06 Stripping one end- Of Said lead Securing Said Stripped 53 Field f Search 29/605, 628 630 R, 630 A; end of said lead to a turn of said winding to form a 336/192, 2077 206 tap, sliding a sleeve of flexible insulating material onto said lead, slitting the end of said sleeve adjacent said [56] References Cited tap forming a flap portion, folding said flap portion of UNITED STATES PATENTS said sleeve about said tap and onto the adjacent portion of said sleeve and overlying said flap portion with g; 29/605 subsequent turns of said winding of said coil. 2,479,400 8/1949 Pecoroni et a1 336/206 2 Cl ims, 8 Drawing Figur s US. Patent Dec. 16, 1975 Sheet 1 012 U.S. Patfint Dec.16,1975 Sheet20f2 3,925,885

METHOD FOR MAKING AND INSULATING A COIL TAP BACKGROUND AND SUMMARY OF THE INVENTION The invention herein relates to a significant improvement in tapping and insulating leads onto various turns of the winding of a coil such as a transformer coil.

It is a common practice to make a loop of the magnet wire of which the coil is wound and have the same extend outwardly of the coil to form a lead and the extended end portion of such a lead is stripped of its insulation and a connection is either bolted thereto or in the alternative a connection is crimped thereonto or clipped thereto.

Another method utilizing less of the magnet wire of the winding comprises stripping a portion of the magnet wire of insulation and soldering the terminal of a lead thereonto and insulating the same with an appropriate pad, the same to be secured by successive turns of the winding.

There appears to be an average of at least six leads tapped onto a transformer coil and there may be many more dependent upon the purpose of the coil. Tapping each lead as above indicated has been found to require an average time on the order of 90 seconds.

The improvement present in the invention herein provides for a substantial reduction in the time required to tap a coil. The method herein has been found to reduce the otherwise time required of 90 seconds per tap to approximately 15 seconds per tap or onesixth of the otherwise time requirement. In view of the average number of taps for each coil wound, this represents a significant reduction in direct labor cost.

It is an object of this invention therefore to provide a method for tapping leads in winding a transformer coil whereby there results a significant reduction in the time required for making a tap.

It is a further object of this invention to simplify the steps required to tap a lead onto the winding of a coil.

More specifically, it is an object of this invention to tap a lead onto the winding of a coil which consists of stripping the end of a lead of insulation, securing said stripped end of said lead onto a turn of the winding of a coil and thus forming a tap, sliding a flexible insulating sleeve onto said lead, slitting the end of said sleeve adjacent said tap to form a flap portion folding said flap portion about said tap and overlying an adjacent portion of said sleeve and securing said flap portion with the successive overlying turns of the winding of said coil.

These and other objects and advantages of the invention will be set forth in the following description made in connection with the accompanying drawings in which like reference characters refer to similar parts throughout the several views and in which:

FIG. 1 is a side view of a coil;

FIG. 2 is a top plan view of the coil shown in FIG. 1;

FIG. 3 is a view in side elevation of an insulating sleeve;

FIG. 4 is a broken exploded view showing separated details of assembly;

FIG. 5 is a broken view showing a partial assembly; and

FIGS. 6, 7 and 8 are successive assembly step views in perspective with portions of FIGS. 7 and 8 being broken away.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to the drawings, FIGS. 1 and 2 show a partially wound coil 10 representing a transformer coil and only as much of said coil is here shown as is believed necessary for a full disclosure of the invention herein. Said coil represents a conventional or common type of coil which, it will be understood, will be mounted for use onto a desired type of metal stack or core not here shown.

Said coil 10 comprises a winding 12 of magnet wire about a core tube 14, said winding consisting of a multiplicityof turns 15. What is shown here is represented as being a portion of the primary winding of said coil.

Shown extending from within the winding of said coil are a plurality of tap leads 18. These are identical for purposes herein. The invention herein relates to a method for attaching said tap leads to turns of said winding and insulating the same.

Referring to FIG. 3, a flexible insulating sleeve 20 is shown and said sleeve may be formed very suitably of woven fiberglass material. Said sleeve is shown having a slit end portion 21 forming aflap portion 22.

Referring to FIG. 4, one of said tap leads 18 is shown having a stripped end portion 26 for attachment to a turn of the winding and a connector 27 is attached to the other or outer end of said tap lead. Said stripped end is shown adjacent a turn 15 of said winding and shown adjacent thereto is securing member 28 shown here as a crimp member or crimp terminal for attaching said stripped end 26 to said turn. The attachment or tap may be mechanically accomplished as by the use of a crimping apparatus not here shown. Said crimp terminal secures the stripped end of the tap lead to the magnet wire and ruptures the insulation overlying the magnet wire for a conductive connection without any preliminary preparation being required of the magnet wire such as stripping .away insulation.

FIG. 5 shows the tap lead 18 attached by the crimp terminal 28 to said turn 15 and thus a tap 29 is formed. Said sleeve 20 is pulled onto said tap lead with its slit end 21 or flap portion 22 being positioned adjacent said attached end of said tap lead.

FIGS. 6 and 7 show the insulating sleeve 20 positioned on the tap lead and the flap portion 22 thereof is shown drawn about the crimp terminal 28 and will overlie the same and extend to overlie the sleeved portion of said tap lead and thus said tap 29 is insulated.

FIG. 8 shows the flap portion 22 overlying the crimped terminal and a portion of the sleeve with a turn 15 being wound thereover to secure the same and subsequent turns will completely overlie and cover said crimped terminal and the tap 29.

The steps set forth above from the time that an operator takes the tap lead in hand to a completion of securing and insulating said tap lead onto the magnet wire and tapping the same is found to be about 15 seconds. Subsequent turns of the winding completely cover the tap thus formed.

The method set forth herein has been very successful commercially in reducing direct labor cost sufficiently to make a coil thus formed very competitive in the marketplace.

It will of course be understood that various changes may be made in the steps and sequence of steps of the method without departing from the scope of applicants invention which, generally stated, consists in a method capable of carrying out the objects above set forth,

such as disclosed and defined in the appended claims.

What is claimed is: 1. A method for tapping a coil and insulating the same, consisting of the steps of stripping the end of a tap lead, applying said stripped end of said tapped lead to a turn of the winding of a coil, crimping said stripped end onto said turn forming a p. applying an insulating sleeve to said tap lead consisting of slitting one end portion of said sleeve forming a flap portion, moving said sleeve onto said tap lead and placing said slit end adjacent said tap, folding said flap portion about said tap insulating the same, and

overlying said flap portion with subsequent turns of said winding securing said flap portion.

2. A method for tapping a coil and insulating the same, consisting of the steps of stripping the end of a tap lead,

applying said stripped end of said tap lead to a turn of the winding of a coil forming a tap,

slitting one end portion of an insulating sleeve form ing a flap portion,

moving said insulating sleeve onto said tap lead and placingsaid slit end adjacent said tap,

folding said flap portion about said tap insulating the same, and

overlying said flap portion with subsequent turns of said winding securing said flap portion. 

1. A method for tapping a coil and insulating the same, consisting of the steps of stRipping the end of a tap lead, applying said stripped end of said tapped lead to a turn of the winding of a coil, crimping said stripped end onto said turn forming a tap, applying an insulating sleeve to said tap lead consisting of slitting one end portion of said sleeve forming a flap portion, moving said sleeve onto said tap lead and placing said slit end adjacent said tap, folding said flap portion about said tap insulating the same, and overlying said flap portion with subsequent turns of said winding securing said flap portion.
 2. A method for tapping a coil and insulating the same, consisting of the steps of stripping the end of a tap lead, applying said stripped end of said tap lead to a turn of the winding of a coil forming a tap, slitting one end portion of an insulating sleeve forming a flap portion, moving said insulating sleeve onto said tap lead and placing said slit end adjacent said tap, folding said flap portion about said tap insulating the same, and overlying said flap portion with subsequent turns of said winding securing said flap portion. 